An inexpensive, disposable device is proposed that collects plasma for diagnostic testing purposes without depleting the patient's red blood cell supply. Intensive care unit patients often require several diagnostic blood tests per day to guide treatment and monitor progress. Frequent phlebotomies performed on these patients over extended periods of time can cumulatively result in anemia, requiring red blood cell transfusion. The proposed device will decrease the incidence of phlebotomy-related anemia by providing plasma for those diagnostic tests that do not require red blood cells. In practice, the device will ultimately decrease cardiac stress levels in patients, reduce need for blood transfusions, and reduce incidence of transfusion-related complications. PROPOSED COMMERCIAL APPLICATIONS: This research and the resultant device product will be used in intensive care units for collecting blood plasma for diagnostic testing. The device is low cost and disposable and reduces health care costs by helping to prevent phlebotomy-related anemia, improving patient health, reducing numbers of blood transfusions performed, and reducing transfusion-related complications.